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Their vertical components are transmitted (shown), while the horizontal components are absorbed and reflected (not shown). Because their polarization vectors depend on incidence angle, polarizers based on Fresnel reflection inherently tend to produce s – p polarization rather than Cartesian polarization [ clarification needed ] , which limits ...
When measuring horizontal fusion ranges, base in prisms assess fusional divergence while base out prisms assess fusional convergence. The vertical fusional vergence amplitude can also be measured with base up and base down prisms although the horizontal PFR is typically the main focus when testing.
The prism cover test (PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment, or a deviation of the eye. It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components.
This line is called the empirical horizontal horopter. There is also an empirical vertical horopter, which is effectively tilted away from the eyes above the fixation point and towards the eyes below the fixation point. The horizontal and vertical horopters mark the centre of the volume of singleness of vision.
The spherical aberration of the cornea is usually positive whereas the young crystalline lens exhibits a negative spherical aberration. Besides, there is strong evidence of compensation for aberrations between the cornea and intraocular optics in cases of astigmatism (horizontal/vertical) and horizontal coma.
The angles in the vertical axis should read 90 ° (100 grad) when the sight axis is horizontal, or 270° (300 grad) when the instrument is transited. Half of the difference between the two positions is called the index error. This can only be checked on transit instruments. Horizontal axis error.
In projective geometry, a cylinder is simply a cone whose apex (vertex) lies on the plane at infinity. If the cone is a quadratic cone, the plane at infinity (which passes through the vertex) can intersect the cone at two real lines, a single real line (actually a coincident pair of lines), or only at the vertex.
The terms horizontal (h) and vertical (v), and the corresponding subscripts, refer to the additional mirror plane, that can be parallel to the rotation axis (vertical) or perpendicular to the rotation axis (horizontal). The simplest nontrivial axial groups are equivalent to the abstract group Z 2: C i (equivalent to S 2) – inversion symmetry
In astronomy, geography, and related sciences and contexts, a direction or plane passing by a given point is said to be vertical if it contains the local gravity direction at that point. [1] Conversely, a direction or plane is said to be horizontal (or leveled) if it is perpendicular to the vertical direction.
The misalignment may be vertical, horizontal or both. The misalignment (a few minutes of arc ) is much smaller than that of strabismus . While strabismus prevents binocular vision , fixation disparity keeps binocular vision, however it may reduce a patient's level of stereopsis .